How to create a generic CRUD controller test in Spock

Question

Is it even possible to create generic unit test for Spring controller in Spock? I have a abstract controller in Spring Boot, which is extended by a few specific controllers. The result is every controller have the same implementation of CRUD. So, for now I want to create similar unit tests for these controllers, but I cant use constructors in Spock Tests. I get error

CrudControllerTest.groovy
Error:(16, 5) Groovyc: Constructors are not allowed; instead, define a 'setup()' or 'setupSpec()' method
IngredientControllerTest.groovy
Error:(7, 5) Groovyc: Constructors are not allowed; instead, define a 'setup()' or 'setupSpec()' method

For belowe code

abstract class CrudControllerTest<T, R extends JpaRepository<T, Long>, C extends CrudController<T,R>> extends Specification {
    private String endpoint
    private def repository
    private def controller
    private MockMvc mockMvc
 
    CrudControllerTest(def endpoint, R repository, C controller) {
        this.endpoint = endpoint
        this.repository = repository
        this.controller = controller
        this.mockMvc = MockMvcBuilders.standaloneSetup(controller).build()
    }
 
    def "Should get 404 when product does not exists"() {
        given:
        repository.findById(1) >> Optional.empty()
        when:
        def response = mockMvc.perform(MockMvcRequestBuilders.get(endpoint + '/1')).andReturn().response
        then:
        response.status == HttpStatus.NOT_FOUND.value()
    }
}
 
class IngredientControllerTest extends CrudControllerTest<Ingredient, IngredientRepository, IngredientController> {
    
    IngredientControllerTest() {
        def repository = Mock(IngredientRepository)
        super("/ingredients", repository, new IngredientController(Mock(repository)))
    }
}

Is here any other way to implement generic unit test in Spock?

Answer 1

You can't use constructors for Specifications instead you can use the template method pattern. Either with separate methods:

abstract class CrudControllerTest extends Specification {
    private String endpoint
    private def repository
    private def controller
    private MockMvc mockMvc
 
    def setup() {
        endpoint = createEndpoint()
        repository = createRepository()
        controller = createController()
        mockMvc = MockMvcBuilders.standaloneSetup(controller).build()
    }
    
    abstract createEndpoint()
    abstract createRepository()
    abstract createController()
 
    def "Should get 404 when product does not exists"() {
        given:
        repository.findById(1) >> Optional.empty()
        when:
        def response = mockMvc.perform(MockMvcRequestBuilders.get(endpoint + '/1')).andReturn().response
        then:
        response.status == HttpStatus.NOT_FOUND.value()
    }
}
 
class IngredientControllerTest extends CrudControllerTest<Ingredient, IngredientRepository, IngredientController> {
    
    def createEndpoint() {
        "/ingredients"
    }
    def createRepository {
        Mock(IngredientRepository)
    }
    def createController() {
        new IngredientController(repository)
    }
}

or with a method that returns everything, which is a bit nicer as some of your values need to reference the other value:

abstract class CrudControllerTest extends Specification {
    private String endpoint
    private def repository
    private def controller
    private MockMvc mockMvc
 
    def setup() {
        (endpoint, repository, controller) = createSut()
        mockMvc = MockMvcBuilders.standaloneSetup(controller).build()
    }
    
    abstract createSut()
 
    def "Should get 404 when product does not exists"() {
        given:
        repository.findById(1) >> Optional.empty()
        when:
        def response = mockMvc.perform(MockMvcRequestBuilders.get(endpoint + '/1')).andReturn().response
        then:
        response.status == HttpStatus.NOT_FOUND.value()
    }
}
 
class IngredientControllerTest extends CrudControllerTest<Ingredient, IngredientRepository, IngredientController> {
    
    def createSut() {
        def repo = Mock(IngredientRepository)
        ["/ingredients", repo, new IngredientController(repository)]
    }
}